Transpulmonary hypothermia: a novel method of rapid brain cooling through augmented heat extraction from the lungs.

AIM: Delay in instituting neuroprotective measures after cardiac arrest increases death and decreases neuronal recovery. Current hypothermia methods are slow, ineffective, unreliable, or highly invasive. We report the feasibility of rapid hypothermia induction in swine through augmented heat extraction from the lungs. METHODS: Twenty-four domestic crossbred pigs (weight, 50-55kg) were ventilated with room air. Intraparenchymal brain temperature and core temperatures from pulmonary artery, lower esophagus, bladder, rectum, nasopharynx, and tympanum were recorded. In eight animals, ventilation was switched to cooled helium-oxygen mixture (heliox) and perfluorocarbon (PFC) aerosol and continued for 90min or until target brain temperature of 32°C was reached. Eight animals received body-surface cooling with water-circulating blankets; eight control animals continued to be ventilated with room air. RESULTS: Brain and core temperatures declined rapidly with cooled heliox-PFC ventilation. The brain reached target temperature within the study period (mean [SD], 66 [7.6]min) in only the transpulmonary cooling group. Cardiopulmonary functions and poststudy histopathological examination of the lungs were normal. CONCLUSION: Transpulmonary cooling is novel, rapid, minimally invasive, and an effective technique to induce therapeutic hypothermia. High thermal conductivity of helium and vaporization of PFC produces rapid cooling of alveolar gases. The thinness and large surface area of alveolar membrane facilitate rapid cooling of the pulmonary circulation. Because of differences in thermogenesis, blood flow, insulation, and exposure to the external environment, the brain cools at a different rate than other organs. Transpulmonary hypothermia was significantly faster than body surface cooling in reaching target brain temperature.

EMS provider compliance with infection control recommendations is suboptimal.

INTRODUCTION: Standard precautions are disease transmission prevention strategies recommended by both the World Health Organization (WHO) and by the Centers for Disease Control and Prevention (CDC). Emergency medical services (EMS) personnel are expected to utilize standard precautions. METHODS: This was a prospective observational study of the use of standard precautions by EMS providers arriving at a large urban emergency department (ED). Research assistants (RAs) observed EMS crews throughout their arrival and delivery of patients and recorded data related to the use of gloves, hand hygiene, and equipment disinfection. RESULTS: A total of 423 EMS deliveries were observed, allowing for observation of 899 EMS providers. Only 512 (56.9%) EMS providers arrived wearing gloves. Hand washing was observed in 250 (27.8%) of providers. Reusable equipment disinfection was noted in only 31.6% of opportunities. The most commonly disinfected item was the stretcher (55%). CONCLUSION: EMS provider compliance with standard precautions and equipment disinfection recommendations is suboptimal. Strategies must be developed to improve EMS provider compliance with internationally recognized infection control guidelines. Key words: Emergency medical services, hand washing, hygiene, disinfection, disease prevention.

Research and Evaluation of Organic Hazardous Air Pollutant Source Emission Test Methods.

Title III of the Clean Air Act Amendments of 1990 has increased the need for well defined and tested stationary source emission sampling and analysis methods. The Methods Branch of the Air Measurements Research Division of U.S. EPA's Office of Research and Development is responsible for a major methods development and evaluation program intended to help fill that need. This paper summarizes recent developments from several of the component projects of that program. Primary emphasis is placed on status and references for methods for organic hazardous air pollutants, such as phosgene, methanol, chloroform, acetonitrile, isocyanates, aldehydes, halogenated organics, non-halogenated organics, and volatile organic material.